Irradiation devices are typically deployed in the form of X-ray devices comprising a radiation source and a radiation receiver. The radiation source emits the radiation, typically X-ray radiation. A collimator, which serves for shaping the beam path or the radiation cone, is connected immediately downstream of the radiation source in most cases. Owing to increased requirements it is aimed to reduce the installation size of such a collimator on irradiation devices of the aforethe type, such as mammography systems or other X-ray systems, for example. The purpose of reducing the size of the collimator is to improve accessibility to the patient. It is furthermore possible to extend the range of movement of the device in view of the fact that the smaller interference contour of the collimator allows a further degree of movement of the carrier arm of the system on which the radiation source and typically also the radiation receiver are arranged. A smaller, narrower collimator essentially enables the system to be kept slimmer in the region of the radiation source also.
A central element in the beam path is the filter device, with the aid of which different filters in the form of metallic filter plates composed of different filter materials having different filter strengths or filter properties can be positioned in the beam path. The installation size of the filter device is matched to the size of the collimator. It is positioned as close as possible in the direction of the focus on the top side of the collimator so that it can be implemented with the smallest possible footprint, and consequently in a space-saving manner.
A known filter device comprises a disk that is rotatable around an axis by way of a corresponding servo motor. Corresponding filter disks, typically three filter disks, are arranged on the disk. The desired filter disk is rotated into the beam path by rotation of the disk. Owing to the integration of the filter device into the collimator or, as the case may be, the collimator housing, the given installation space is utilized to the limit, not least with regard to the fact that a further aim is of course to implement the collimator itself in as compact a design as possible.